Studies on the TiO2 modified microchannels for microfluidic applications

Based on their photoinduced hydrophilicity, titanium dioxide (TiO2) thin films have many promising applications, such as anti-fog, self-cleaning, capillary pump and so on. Microchannels were prepared on glass substrates by wet-etching methods and highly uniform TiO2 thin films were deposited into the micro-channels using pulsed laser deposition (PLD). The crystallite was determined as anatase by X-ray diffraction (XRD); the thickness and the particle size were calculated to be 200 nm and 25 nm respectively. The light absorbance and a contact angle were also investigated using a UV–Visible spectrometer and contact angle analysis system, respectively. The results show that the obtained TiO2 thin films exhibit hydrophilicity. The minimum contact angle was about 10° (highly hydrophilicity) under UV (253.7 nm) light irradiation. The contact angle increased gradually after the light was cut off. The flow velocity of the water in the microchannels was also investigated. The results indicate that the microchannels decorated with TiO2 thin films have promising application in capillary pumps.

► Unique TiO2 thin films were deposited into the microchannels on glass substrates using pulse laser deposition.
► The microchannels deposited TiO2 exhibits super-hydrophilic properties under UV light irradiation.
► The photo-induced hydrophilic capability produced a water fluid rate of 48 mm/s, which can be used to drive fluids.